Athena kit, any news?

Anyone hear anything on the 290 kit? What is their website, I found a athena site but there was nothing on it.

Athena has been know for bad cylinder coatingon the 290 kit. They dont give you the jets that you need. The website doesnt tell any thing. Call up thumper racing 903-938-3340 they have a 290 kit they sleve you stock cylinder and give you a weisco piston which has higher compression than the athena.They also give you something for your oil like a fitting or something i cant remember but I am sending my kit to them. The kit isnt on there website

Are you sure you are not refering to the 270 kit? I do not see a 290 kit on their list

Yeah i hope they come out with it soon.I plan on an engine overhaul this winter.New crank/rod piston ect....I hope that since athena gives you a new cylinder it will have increased cooling to handle bigger displacement.Also does anyone have a friend that used the 290 kit in there yzf or kfx and how did it work out.

I don't mean to rain on anybodys parade, but there will not be a "practical" 290 kit from Athena, or anybody else for that matter. To get the CRF 250 to 290cc would require boring the engine cases at the is why. The barrel measures 85 mm in diameter at the "spigot" or "skirt" that slips into the engine cases. The piston diameter required to make a CRF 250 a 289cc, would have to be 84 mm in diameter, leaving only a cylinder wall thickness of .5 mm (less than .020") at the spigot. Even using a ductile liner (Thumper Racing), prudence dictates at least a 2mm wall thickness, and Garys 270 kit, with an 81mm piston, is slightly more than 2 mm wall at the skirt (As well as being wider, and longer, for added strength). So unless you want to pull the engine down and bore the cases to accept a larger diameter cylinder skirt, it ain't gonna' work. Remember the stock aluminum cylinder skirts were prone to break, and they are 3.5 mm thick.

So how can Athena make it work for the yz and kx and not the crf.

They have a different bore, stroke, and cylinder diameter.

theres also the water pasages in the cylinder head that have to be considered if the bore is to close to them not leaving enough material for sealing of the head gasket it could be a problem and why the athena kit has not been released and may never be released

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